The global population is congregating in our cities. Eighty per cent of the world’s estimated nine billion people in 2050 are expected to live in urban areas. Our cities and urban areas face many challenges from social to health to environmental. The impacts of cities and urban areas are felt in other regions which supply cities with food, water and energy and absorb pollution and waste. However, the proximity of people, businesses and services associated with the very word ‘city’ means that there are also huge opportunities. Indeed, well designed, well managed urban settings offer a key opportunity for sustainable living.